// httpd - attempt at implementing a local HTTP daemon in java
// Mostly stolen from Java in a Nutshell, pp. 145-147
// The rest authored by John Comeau <jcomeau@world.std.com>
// Notes:
/* 1. So far it only works with Netscape. (I have version 1.22.)
    IE 3.0 and Cello both hang unless I set the boolean "suicide" to true,
    in which case Cello will show the page and IE pops up a dialogue box
    informing you that the server was reset. Apparently both IE and Cello
    expect the server to close the connection, and I have no idea what else
    IE wants to see before it will show me a page. Only Netscape seems smart
    enough to realize when a file is done transmitting.
   2. Putting in a schlock 5-sec time delay makes it work with both Netscape
    and IE.
   3. 4/12/97 removing join(), now works OK with all three. Had to remove
    check for "HTTP/1.0" because Cello doesn't issue it on subsequent GETs.
    Also don't use "localhost" with Cello, use 127.0.0.1 instead.
*/
import java.io.*;
import java.net.*;
import java.util.*;

public class httpd extends Thread {
    public final static int DEFAULT_PORT = 80;
    protected int port;
    protected ServerSocket listen_socket;
    protected Watchdog watchdog;
    protected int errors;
    public static final boolean debug = true;
    public static final boolean suicide = false; // die after first customer

/* Log an error message. Make sure to redirect STDOUT if you want a logfile.
For example,
C:\> httpd >%temp%\httpd.log
*/
    public static void log(String str) {
        System.out.println(new Date().toGMTString() + " - " + str);
    }
    // Exit with an error message, when an exception occurs
    public static void fail(Exception e, String msg) {
        log(msg + ": " + e);
        System.exit(1);
    }

    // Create a ServerSocket on which to listen for connections
    // Then start the thread
    public httpd(int port) {
        if(port == 0) port = DEFAULT_PORT;
        this.port = port;
        try { listen_socket = new ServerSocket(port); }
        catch (IOException e) {fail(e, "Exception creating server socket");}
        System.out.println("HTTP Server: Listening on port " + port);
        watchdog = new Watchdog(this);
        this.start();
    }

    // The body of the server thread
    public void run() {
        while (true) {
            try {
                Socket client_socket = listen_socket.accept();
                Connection c = new Connection(client_socket);
                if (suicide) {
                    c.join(0); // wait for connection to die...
                    break;
                }
            }
            catch (Exception e) {
                log("Nonfatal error in run(): " + e);
                this.errors++;
            }
        }
    }

    // Start the server up, listening on an optionally specified port
    public static void main(String[] args) {
        int port = 0;
        if (args.length == 1) {
            try {port = Integer.parseInt(args[0]);}
            catch (NumberFormatException e) {port = 0;}
        }
        new httpd(port);
    }
}

// This class handles all communication with a client
class Connection extends Thread {
    protected Socket client;
    protected DataInputStream in;
    protected PrintStream out;
    protected Vector request;
    protected StringTokenizer getfile;
    protected File file;
    public final static String HOMEPAGE = "/index.html";
    protected byte[] buffer;
    String line;
    String cmdline;
    String command;
    String filename;
    String protocol;
    String type;
    boolean badrequest;
    public static final boolean debug = true;
    public static final boolean delay = true;

    // Initialize the streams and start the thread
    public Connection(Socket client_socket) {
        client = client_socket;
        try {
            in = new DataInputStream(client.getInputStream());
            out = new PrintStream(client.getOutputStream());
        }
        catch (IOException e) {
            try {client.close();} catch (IOException e2) {;}
            System.out.println("Exception while getting socket streams " + e);
            return;
        }
        this.start();
    }

    // provide the service
    public void run() {
        try {
            request = new Vector();
            for(;;) {
                // read in a line
                line = in.readLine();
                if (line == null || line.trim().length() == 0) break;
                System.out.println(line); // show what we got
                request.addElement(line.trim());
            }
            System.out.println("Responding to client...");
            if (debug) {
                System.out.println("Address=" + client.getInetAddress());
                System.out.println("Port=" + client.getPort());
                System.out.println("Local Port=" +
                    client.getLocalPort());
            }
            command = ""; // init to null strings
            filename = "";
            protocol = "";
            try {
                getfile = new StringTokenizer(
                    request.elementAt(0).toString());
                command = getfile.nextToken(); // GET or HEAD, no POST
                filename = getfile.nextToken();
                protocol = getfile.nextToken();
            } catch (Exception e) {
                if (filename.equals("")) badrequest = true;
                if (debug) {
                    System.out.println("Error parsing command: command=" +
                    command + ", filename=" + filename + ", protocol=" +
                    protocol);
                }
            }
            try {
                if (                                                                      !command.equals("GET") && !command.equals("HEAD"))
                badrequest = true;
            } catch (Exception e) { badrequest = true; }
            if (badrequest) {
                if (debug) {
                    System.out.println("Error interpreting command: command=" +
                    command + ", filename=" + filename + ", protocol=" +
                    protocol);
                }
                out.print("HTTP/1.0 403 NFW\r\n");
                out.print("Server: Java1.0\r\n");
                out.print("Date: " + new Date().toGMTString() + "\r\n");
                out.print("Content-Type: text/html\r\n\r\n");
                out.print("<HTML><BODY><H1>No Freakin' Way!" +
                    "</H1></BODY></HEAD>\r\n\r\n");
                return; // goes to "finally" clause below before exiting
            }
            if (filename.equals("/")) filename = HOMEPAGE;
            try {
                file = new File(filename);
                in = new DataInputStream(new FileInputStream(file));
                buffer = new byte[(int) file.length()]; in.read(buffer);
            } catch (Exception e) {
                out.print("HTTP/1.0 404 Not Found\r\n");
                out.print("Server: Java1.0\r\n");
                out.print("Date: " + new Date().toGMTString() + "\r\n");
                out.print("Content-Type: text/html\r\n\r\n");
                out.print("<HTML><BODY><H1>Say what???" +
                "</H1></BODY></HEAD>\r\n\r\n");
                return; // to "finally" block below
            }
            out.print("HTTP/1.0 200 OK\r\n");
            out.print("Server: Java1.0\r\n");
            out.print("Date: " + new Date().toGMTString() + "\r\n");
            try { type = filename.substring(
                filename.lastIndexOf('.') + 1).toLowerCase(); }
            catch (StringIndexOutOfBoundsException e) { type = ""; }
            if (debug) System.out.println("Type=\"" + type + "\"");
            out.print("Content-Type: ");
            if (type.equals("txt")) out.print("text/plain\r\n");
            else if (type.equals("jpg") || type.equals("jpeg"))
                out.print("image/jpeg\r\n");
            else if (type.equals("gif")) out.print("image/gif\r\n");
            else out.print("text/html\r\n");
            out.print("Content-Length: " + file.length() + "\r\n\r\n");
            if (command.equals("GET")) out.write(buffer);
        }
        catch (Exception e){;}
        finally {
            if (delay) try {sleep(5000);} catch (Exception e) {;}
            try {client.close();} catch (IOException e) {
                System.out.println(e); }
            System.out.println("Closed connection to client...");
            this.stop();
        }
    }
}
// Put watchdog to work, cleaning up if 10 errors or more in a second

class Watchdog extends Thread {
    protected httpd server;
    protected Watchdog(httpd s) {
        server = s;
        this.start();
    }
// should really synchronize on errors but I don't know how...
    public synchronized void run() {
        for (;;) {
            try {this.wait(1000);} catch (InterruptedException e) {;}
            if (server.errors >= 10) {
                server.log(server.errors +
                    " errors logged in one second, aborting...");
                System.exit(1);
            } else {
                server.errors = 0;
            }
        }
    }
}